These slotted 1/4-20 set screws are used with vintage style door knobs mounted on threaded spindles. The screw threads through the knob shank and tightens directly onto the spindle (not to be confused with headed set screws used for tightening knobs onto tapped spindles). Made of brass-plated steel.

Dimensions: 1/4" in diameter by 5/16" in length, with 20 threads per inch.